Some ink-jet printers, such as manufactured by Hewlett-Packard Company under the designation DeskJet, include a cartridge or "pen" that is mounted to the printer. The pen includes a body that defines a reservoir of ink, and a print head that is operated for ejecting minute ink drops onto paper that is advanced through the printer.
Prior ink-jet pens have been constructed so that the print head is irremovably attached to the pen body, thereby preventing replacement of a print head without damage to the pen.
The present invention is directed to a construction whereby ink-jet printer pens have modular or unit print head assemblies that can be readily mounted to and removed from a pen body or carriage in the event that the assembly needs repair or replacement. Moreover, the print heads of an individual unit print head assembly may be fully tested before that assembly is joined with several other parts in constructing a pen.
Also provided is a mechanism for ensuring that the electrical connection between the assembly and carriage is sealed from exposure to liquids such as ink.